Any ideas what it could have been?
New tank and parameters always perfect (am 0, nitrites 0, nitrates 0, ph 8, salinity .23-.25, temp 79-80) it is a bio cube hqi 29 with koralia 420 and mp-10, 20-25 lbs lr
and a little macro rock. In tank media basket with filter floss pyrogens and chemo pure elite, lr
rubble in refugium. Mj1200 pump upgrade with bio cube skimmer. Used stability with lr
to get tank going and parameters always perfect...I test every 2nd day. Put in a peppermint shrimp and clown (big Al's ) on 5th day and it was shy at first then doing awesome. Ate from day 1..everything. 14 days after put in another smaller clown from reputable online dealer. Fish was very shy and did not eat for 7-10 days...at least from what I could see. Original clown took to it right away swimming beside always. About 5 days ago original clown suddenly stopped eating while smaller clown began eating. 2 days ago 1 white sand like spot on original clown and swollen lips and mouth remained open. Today...dead. Clown continued swimming normally right till end. No scraping on anything or swimming weird. Other clown and shrimp eating and seem normal. Parameters still same. Everything drip acclimated for 2 hour. Any ideas from experts around here? I attached pics.